- Histologically or cytologically confirmed recurrent GBM in 1st or 2nd relapse: Primary Cohort: Recurrence following radiation therapy and temozolomide, less than or equal to 2 prior chemotherapeutic regimens; Exploratory cohort: Prior radiation therapy, temozolomide, and bevacizumab, Recurrence of disease within 2-4 weeks of last bevacizumab dose.